Questions tagged [latency]
The latency tag has no usage guidance.
37
questions
2
votes
1
answer
60
views
Solving the USB drive/mass storage stall issue
Sadly the issue reported and described here: Pernicious USB-stick stall problem. Reverting workaround fix? and Is "writeback throttling" a solution to the "USB-stick stall problem"?...
- 30.7k
0
votes
0
answers
30
views
iperf3 doesn't find network bandwidth difference but curl does
I have 1 client (A) and 2 servers (B & C). Servers were using different amounts of CPU with load balancing and i wanted to root cause it. I suspected it could be a network speed issue so I ran an ...
1
vote
0
answers
66
views
SSH client with instant input echo
When using the terminal on code-server (VSCode probably does it as well), input is instantly shown on screen (grayed out, until the server actually responds):
When I connect to the remote machine ...
- 233
0
votes
1
answer
223
views
How to measure TCP latency?
OS is Debian on both servers.
I found some examples showing how to measure TCP latency with nmap:
nmap --packet-trace -p 22 192.168.0.10
But I'm getting some negative results for latency. ie, it will ...
- 487
2
votes
2
answers
8k
views
How do you install the linux-lowlatency kernel and why does it stops at version 5.15?
I have been reading today about linux-lowlatency and I am more and more confused. First of all, is the install as simple as sudo apt install linux-lowlatency and then reboot? Do I need to select a ...
- 117
-1
votes
1
answer
75
views
http latency wild variance on localhost
Running on MBP M1 with 10 cores.
Running 1 thread client (wrk) and 1 thread server (java).
A youtube is also running on the system.
Load average 2 out of 10.
Except GC, which could be the reasons of ...
- 99
0
votes
1
answer
780
views
vim very slow over SSH connection
I have a non-stellar SSH connection to some machine; the echo time is... I don't know, 0.2 seconds or so.
Anyway, when I start vim, say with no input file, I experience a long delay, of about 3 to 4 ...
- 9,653
2
votes
1
answer
371
views
strange issue, worst network speed and worst ping latency on linux
I cannot explain this, I will start by listing these speed test results
this one is the linux host running mxlinux latest version
this one is the windows 10 running inside vmware on the same computer
...
- 131
0
votes
0
answers
252
views
strace with errors on openat syscall with Lustre FS, RHEL 8, overall intermittent latency
Does anyone see what could be causing this intermittent latency? At various times all commands become slow on login, compute and head nodes and only with logins associated with Lustre, i.e., root and ...
- 133
1
vote
0
answers
332
views
How to tune Linux kernel to try to keep free RAM ready?
I have a system with very spikey memory usage and lots of disk activity. As such, I'd like to have files in the cache as much as possible but I'd like to have enough free RAM ready to go to quickly ...
- 4,219
1
vote
1
answer
798
views
How to change the default BDI `max_ratio` and/or `min_ratio` for all devices?
I'm using a system with multiple storage devices with different write throughput. As explained in question Why were "USB-stick stall" problems reported in 2013? Why wasn't this problem ...
- 4,219
0
votes
1
answer
547
views
Reduce microsecond jitter (using realtime kernel)
I have a raspberry pi 4B running Gentoo, with the 5.15.44 raspi kernel & realtime patches applied to it. The kernel is configured for CONFIG_PREEMPT_RT (big surprise), as well as ...
- 1
1
vote
0
answers
236
views
Add extra latency on top of existing tc qdiscs
On a system with an existing multi-stage qdisc setup, we need to introduce extra latency (at least fixed, but fixed with a small variation would be a nice option to have).
The canonical way to do this ...
- 1,752
0
votes
0
answers
413
views
Low-Latency method to read Xorg or DRM framebuffer
I am trying to build an application that can measure the latency/processing time of graphics frameworks on Linux.
My idea is to implement simple programs that react to an input event (e.g. mouse click)...
0
votes
1
answer
741
views
Copying a same file multiple times
I have an audio file, and I am running a script to decode that audio file. Now I want to measure the latency of the system.
So, I am running a script with a time command.
like $ time ./uber.sh
In the ...
- 125